[PATCH v3 03/81] drm/fbdev: Add memory-agnostic fbdev client
Thomas Zimmermann
tzimmermann at suse.de
Fri Aug 30 08:39:47 UTC 2024
Add an fbdev client that can work with any memory manager. The
client implementation is the same as existing code in fbdev-dma or
fbdev-shmem.
Provide struct drm_driver.fbdev_probe for the new client to allocate
the surface GEM buffer. The new callback replaces fb_probe of struct
drm_fb_helper_funcs, which does the same.
To use the new client, DRM drivers set fbdev_probe in their struct
drm_driver instance and call drm_fbdev_client_setup(). Probing and
creating the fbdev surface buffer is now independent from the other
operations in struct drm_fb_helper. For the pixel format, the fbdev
client either uses a specified format, the value in preferred_depth
or 32-bit RGB.
v2:
- test for struct drm_fb_helper.funcs for NULL (Sui)
- respect struct drm_mode_config.preferred_depth for default format
Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
drivers/gpu/drm/Makefile | 4 +-
drivers/gpu/drm/drm_fb_helper.c | 15 +--
drivers/gpu/drm/drm_fbdev_client.c | 141 +++++++++++++++++++++++++++++
include/drm/drm_drv.h | 18 ++++
include/drm/drm_fbdev_client.h | 19 ++++
5 files changed, 190 insertions(+), 7 deletions(-)
create mode 100644 drivers/gpu/drm/drm_fbdev_client.c
create mode 100644 include/drm/drm_fbdev_client.h
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 68cc9258ffc4..0beb55d028a8 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -144,7 +144,9 @@ drm_kms_helper-y := \
drm_self_refresh_helper.o \
drm_simple_kms_helper.o
drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o
-drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
+drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += \
+ drm_fbdev_client.o \
+ drm_fb_helper.o
obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
#
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 13095d38aa42..44bc92caf58a 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -492,8 +492,8 @@ EXPORT_SYMBOL(drm_fb_helper_init);
* @fb_helper: driver-allocated fbdev helper
*
* A helper to alloc fb_info and the member cmap. Called by the driver
- * within the fb_probe fb_helper callback function. Drivers do not
- * need to release the allocated fb_info structure themselves, this is
+ * within the struct &drm_driver.fbdev_probe callback function. Drivers do
+ * not need to release the allocated fb_info structure themselves, this is
* automatically done when calling drm_fb_helper_fini().
*
* RETURNS:
@@ -1612,7 +1612,7 @@ static int drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
/*
* Allocates the backing storage and sets up the fbdev info structure through
- * the ->fb_probe callback.
+ * the ->fbdev_probe callback.
*/
static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
{
@@ -1631,7 +1631,10 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
}
/* push down into drivers */
- ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
+ if (dev->driver->fbdev_probe)
+ ret = dev->driver->fbdev_probe(fb_helper, &sizes);
+ else if (fb_helper->funcs)
+ ret = fb_helper->funcs->fb_probe(fb_helper, &sizes);
if (ret < 0)
return ret;
@@ -1705,7 +1708,7 @@ static void drm_fb_helper_fill_var(struct fb_info *info,
* instance and the drm framebuffer allocated in &drm_fb_helper.fb.
*
* Drivers should call this (or their equivalent setup code) from their
- * &drm_fb_helper_funcs.fb_probe callback after having allocated the fbdev
+ * &drm_driver.fbdev_probe callback after having allocated the fbdev
* backing storage framebuffer.
*/
void drm_fb_helper_fill_info(struct fb_info *info,
@@ -1861,7 +1864,7 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
* Note that this also registers the fbdev and so allows userspace to call into
* the driver through the fbdev interfaces.
*
- * This function will call down into the &drm_fb_helper_funcs.fb_probe callback
+ * This function will call down into the &drm_driver.fbdev_probe callback
* to let the driver allocate and initialize the fbdev info structure and the
* drm framebuffer used to back the fbdev. drm_fb_helper_fill_info() is provided
* as a helper to setup simple default values for the fbdev info structure.
diff --git a/drivers/gpu/drm/drm_fbdev_client.c b/drivers/gpu/drm/drm_fbdev_client.c
new file mode 100644
index 000000000000..a09382afe2fb
--- /dev/null
+++ b/drivers/gpu/drm/drm_fbdev_client.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: MIT
+
+#include <drm/drm_client.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fbdev_client.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_print.h>
+
+/*
+ * struct drm_client_funcs
+ */
+
+static void drm_fbdev_client_unregister(struct drm_client_dev *client)
+{
+ struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
+
+ if (fb_helper->info) {
+ drm_fb_helper_unregister_info(fb_helper);
+ } else {
+ drm_client_release(&fb_helper->client);
+ drm_fb_helper_unprepare(fb_helper);
+ kfree(fb_helper);
+ }
+}
+
+static int drm_fbdev_client_restore(struct drm_client_dev *client)
+{
+ drm_fb_helper_lastclose(client->dev);
+
+ return 0;
+}
+
+static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
+{
+ struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
+ struct drm_device *dev = client->dev;
+ int ret;
+
+ if (dev->fb_helper)
+ return drm_fb_helper_hotplug_event(dev->fb_helper);
+
+ ret = drm_fb_helper_init(dev, fb_helper);
+ if (ret)
+ goto err_drm_err;
+
+ if (!drm_drv_uses_atomic_modeset(dev))
+ drm_helper_disable_unused_functions(dev);
+
+ ret = drm_fb_helper_initial_config(fb_helper);
+ if (ret)
+ goto err_drm_fb_helper_fini;
+
+ return 0;
+
+err_drm_fb_helper_fini:
+ drm_fb_helper_fini(fb_helper);
+err_drm_err:
+ drm_err(dev, "fbdev: Failed to setup emulation (ret=%d)\n", ret);
+ return ret;
+}
+
+static const struct drm_client_funcs drm_fbdev_client_funcs = {
+ .owner = THIS_MODULE,
+ .unregister = drm_fbdev_client_unregister,
+ .restore = drm_fbdev_client_restore,
+ .hotplug = drm_fbdev_client_hotplug,
+};
+
+/**
+ * drm_fbdev_client_setup() - Setup fbdev emulation
+ * @dev: DRM device
+ * @format: Preferred color format for the device. DRM_FORMAT_XRGB8888
+ * is used if this is zero.
+ *
+ * This function sets up fbdev emulation. Restore, hotplug events and
+ * teardown are all taken care of. Drivers that do suspend/resume need
+ * to call drm_fb_helper_set_suspend_unlocked() themselves. Simple
+ * drivers might use drm_mode_config_helper_suspend().
+ *
+ * This function is safe to call even when there are no connectors present.
+ * Setup will be retried on the next hotplug event.
+ *
+ * The fbdev client is destroyed by drm_dev_unregister().
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int drm_fbdev_client_setup(struct drm_device *dev, const struct drm_format_info *format)
+{
+ struct drm_fb_helper *fb_helper;
+ unsigned int color_mode;
+ int ret;
+
+ /* TODO: Use format info throughout DRM */
+ if (format) {
+ unsigned int bpp = drm_format_info_bpp(format, 0);
+
+ switch (bpp) {
+ case 16:
+ color_mode = format->depth; // could also be 15
+ break;
+ default:
+ color_mode = bpp;
+ }
+ } else {
+ switch (dev->mode_config.preferred_depth) {
+ case 0:
+ case 24:
+ color_mode = 32;
+ break;
+ default:
+ color_mode = dev->mode_config.preferred_depth;
+ }
+ }
+
+ drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
+ drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
+
+ fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
+ if (!fb_helper)
+ return -ENOMEM;
+ drm_fb_helper_prepare(dev, fb_helper, color_mode, NULL);
+
+ ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);
+ if (ret) {
+ drm_err(dev, "Failed to register client: %d\n", ret);
+ goto err_drm_client_init;
+ }
+
+ drm_client_register(&fb_helper->client);
+
+ return 0;
+
+err_drm_client_init:
+ drm_fb_helper_unprepare(fb_helper);
+ kfree(fb_helper);
+ return ret;
+}
+EXPORT_SYMBOL(drm_fbdev_client_setup);
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 02ea4e3248fd..36a606af4ba1 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -34,6 +34,8 @@
#include <drm/drm_device.h>
+struct drm_fb_helper;
+struct drm_fb_helper_surface_size;
struct drm_file;
struct drm_gem_object;
struct drm_master;
@@ -366,6 +368,22 @@ struct drm_driver {
struct drm_device *dev, uint32_t handle,
uint64_t *offset);
+ /**
+ * @fbdev_probe
+ *
+ * Allocates and initialize the fb_info structure for fbdev emulation.
+ * Furthermore it also needs to allocate the DRM framebuffer used to
+ * back the fbdev.
+ *
+ * This callback is mandatory for fbdev support.
+ *
+ * Returns:
+ *
+ * 0 on success ot a negative error code otherwise.
+ */
+ int (*fbdev_probe)(struct drm_fb_helper *fbdev_helper,
+ struct drm_fb_helper_surface_size *sizes);
+
/**
* @show_fdinfo:
*
diff --git a/include/drm/drm_fbdev_client.h b/include/drm/drm_fbdev_client.h
new file mode 100644
index 000000000000..e11a5614f127
--- /dev/null
+++ b/include/drm/drm_fbdev_client.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: MIT */
+
+#ifndef DRM_FBDEV_CLIENT_H
+#define DRM_FBDEV_CLIENT_H
+
+struct drm_device;
+struct drm_format_info;
+
+#ifdef CONFIG_DRM_FBDEV_EMULATION
+int drm_fbdev_client_setup(struct drm_device *dev, const struct drm_format_info *format);
+#else
+static inline int drm_fbdev_client_setup(struct drm_device *dev,
+ const struct drm_format_info *format)
+{
+ return 0;
+}
+#endif
+
+#endif
--
2.46.0
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